The weeklong Merrie Monarch Festival in Hilo begins with a public, free celebration, the Ho‘olaule‘a, on Sunday. The cultural festival is expected to draw thousands of visitors to Hilo and surrounding areas — a phenomenon that’s good for tourism revenue, but could pose threats to Hawaii island’s beleaguered, endemic ohia forests. These sites are threatened by rapid ohia death, a fungal plant disease that can be spread from one tree to another during a harvest of material for lei-making.

To notify visitors of the threat, the state Department of Agriculture has issued a reminder: Ohia can be brought to Hawaii island, but it cannot be taken out.